Featured Research

from universities, journals, and other organizations

No link between fertility drugs and breast, ovarian, uterine cancers, study finds

Date:
June 30, 2014
Source:
European Society of Human Reproduction and Embryology
Summary:
There is 'little evidence' that the use of conventional fertility hormones used for ovarian stimulation in the treatment of infertility increases the long-term risk of breast and gynecological cancers, according to the results of a substantial 30-year follow-up study. The study was a retrospective investigation involving 12,193 women treated for infertility between 1965 and 1988 at five US sites. A total of 9,892 women were successfully followed for cancer outcomes.

There is "little evidence" that the use of conventional fertility hormones used for ovarian stimulation in the treatment of infertility increases the long-term risk of breast and gynecological cancers, according to the results of a substantial 30-year follow-up study. However, the extended use of clomiphene citrate was associated with a higher risk of breast cancer among women who had used the fertility drug for 12 cycles or more. Gonadotrophins, more commonly used for ovarian stimulation today, were not generally associated with any increased risk, except in a sub-group of women who remained childless after treatment.

Results of the study, which was in part funded by the National Institutes of Health of the USA, are presented today at the Annual Meeting of ESHRE by Dr Humberto Scoccia from the University of Illinois at Chicago, USA. Dr Louise Brinton of the US National Cancer Institute was principal investigator.(1)

The study was a retrospective investigation involving 12,193 women treated for infertility between 1965 and 1988 at five US sites. Follow-up lasted until 2010, with evaluation based on questionnaire and linkage to US death and cancer registries. A total of 9,892 women were successfully followed for cancer outcomes.

As background to the study Dr Scoccia explained that fertility drugs are known to increase levels of the principal female hormones estradiol and progesterone, both of which have been implicated in the pathogenesis of breast, ovarian and uterine cancers. Drugs to stimulate the ovaries for ovulation induction and IVF have included clomiphene and fertility hormones derived from human subjects -- human menopausal gonadotrophins, hMG, and follicle stimulating hormone, FSH. Both hMG and FSH were not introduced into widespread use until the very early 1980s -- and until then clomiphene was the most commonly used agent.(2)

"Despite the biologic plausibility, results of studies of fertility drugs and breast and gynecological cancers present a mixed picture, with some showing increases in risk, others decreases, and still others showing no substantial associations," said Dr Scoccia. "However, most of these studies had small numbers with relatively short follow-up periods, and were unable to control for other cancer predictors -- including the indications for drug usage, such as anovulation or endometriosis, which could independently affect cancer risk. Many questions remain unresolved."

Over the 30 years of follow-up 749 breast, 119 endometrial (uterine) and 85 ovarian cancers were identified in the 9,892 subjects. The "ever use" of clomiphene -- which included approximately 40% of the cohort -- was not associated with any increased breast cancer risk, except when subjects had used the drug in 12 or more treatment cycles. In such cases clomiphene use was associated with a significant hazard ratio of invasive breast cancer of 1.69 (95% CI 1.16-2.45). This risk remained relatively unchanged after adjustment for causes of infertility and multiple breast cancer predictors. Clomiphene use was not significantly associated with either endometrial (HR 1.41, 95% CI 0.98-2.04) or ovarian (HR 1.34, 95% CI 0.86-2.07) cancers, even when multiple exposure cycles were involved.

Only 10% of the cohort had been treated with gonadotrophins (hMG and FSH) -- usually in combination with clomiphene -- and there was no association with cancer risk identified, except in those who remained childless (HR 1.98; 95% CI, 1.04-3.60). "Given that the majority of our women who received gonadotrophins also received clomiphene," said Dr Scoccia, "it is likely that the increased risk among nulligravid women reflects an effect on risk of their infertility rather than that of drug usage."

In making further comment, he said that the study's findings do not support "a strong relationship" between the use of fertility drugs (mainly clomiphene citrate) and breast, uterine and ovarian cancers. He described the results as "generally reassuring," noting that this study had considerably more statistical power than previous efforts. However, despite the long follow-up of this study he urged continuous monitoring because of the "relatively young age of our study population and the later peak incidence of most of these cancers." It is also likely that the proportion of patients using gonadotrophins for ovarian stimulation -- particularly in IVF -- increased substantially after the mid-1980s.


Story Source:

The above story is based on materials provided by European Society of Human Reproduction and Embryology. Note: Materials may be edited for content and length.


Cite This Page:

European Society of Human Reproduction and Embryology. "No link between fertility drugs and breast, ovarian, uterine cancers, study finds." ScienceDaily. ScienceDaily, 30 June 2014. <www.sciencedaily.com/releases/2014/06/140630094743.htm>.
European Society of Human Reproduction and Embryology. (2014, June 30). No link between fertility drugs and breast, ovarian, uterine cancers, study finds. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2014/06/140630094743.htm
European Society of Human Reproduction and Embryology. "No link between fertility drugs and breast, ovarian, uterine cancers, study finds." ScienceDaily. www.sciencedaily.com/releases/2014/06/140630094743.htm (accessed July 29, 2014).

Share This




More Health & Medicine News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Ebola Virus Threatens West Africa

Deadly Ebola Virus Threatens West Africa

AP (July 28, 2014) West African nations and international health organizations are working to contain the largest Ebola outbreak in history. It's one of the deadliest diseases known to man, but the CDC says it's unlikely to spread in the U.S. (July 28) Video provided by AP
Powered by NewsLook.com
$15B Deal on Vets' Health Care Reached

$15B Deal on Vets' Health Care Reached

AP (July 28, 2014) A bipartisan deal to improve veterans health care would authorize at least $15 billion in emergency spending to fix a veterans program scandalized by long patient wait times and falsified records. (July 28) Video provided by AP
Powered by NewsLook.com
Two Americans Contract Ebola in Liberia

Two Americans Contract Ebola in Liberia

Reuters - US Online Video (July 28, 2014) Two American aid workers in Liberia test positive for Ebola while working to combat the deadliest outbreak of the virus ever. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins